An automated, high-throughput methodology optimized for quantitative cell-free mitochondrial and nuclear DNA...

Area of Science:

• Biochemistry
• Molecular Biology
• Clinical Diagnostics

Background:

• Circulating cell-free nuclear DNA (ccf-nDNA) and mitochondrial DNA (ccf-mtDNA) show promise as biomarkers for cancer detection.
• Current isolation protocols for ccf-mtDNA are suboptimal, and inconsistencies in ccf-nDNA handling limit clinical utility.
• No established high-throughput methods exist for simultaneously isolating both ccf-nDNA and ccf-mtDNA.

Purpose of the Study:

• To develop and optimize a high-throughput method for the simultaneous isolation of ccf-nDNA and ccf-mtDNA from human plasma.
• To address challenges in reproducibility and recovery associated with existing isolation techniques on automated platforms.
• To establish a robust protocol for improved clinical utility of circulating cell-free DNA in disease diagnostics.

Main Methods:

• Optimization of human plasma digestion and magnetic bead-based extraction conditions for maximal DNA recovery.
• Development of a detailed protocol for an automated 96-well platform to overcome plate edge effects and improve reproducibility.
• Systematic adjustment of digestion conditions, liquid handling, and magnetic particle processor programming.

Main Results:

• Achieved significantly improved recovery efficiencies: approximately 95-fold for ccf-mtDNA and 20-fold for ccf-nDNA compared to initial procedures.
• Demonstrated high reproducibility and eliminated positional effects on the automated platform.
• Successfully established the first high-throughput isolation method optimized for both ccf-mtDNA and ccf-nDNA.

Conclusions:

• The developed high-throughput protocol enhances the recovery of both ccf-nDNA and ccf-mtDNA.
• This optimized method overcomes previous limitations in reproducibility and throughput for circulating cell-free DNA isolation.
• The protocol serves as a critical foundation for future clinical studies and the advancement of noninvasive diagnostic tests.